refactor invoice amount checks

controllers/keysend.ctrl.go

@@ -91,7 +91,7 @@ func (controller *KeySendController) KeySend(c echo.Context) error {
 
 	minimumBalance := invoice.Amount
 	if controller.svc.Config.FeeReserve {
-		minimumBalance += invoice.CalcFeeLimit(controller.svc.IdentityPubkey)
+		minimumBalance += controller.svc.CalcFeeLimit(invoice.DestinationPubkeyHex, invoice.Amount)
 	}
 	if currentBalance < minimumBalance {
 		c.Logger().Errorf("User does not have enough balance invoice_id:%v user_id:%v balance:%v amount:%v", invoice.ID, userID, currentBalance, invoice.Amount)

controllers/payinvoice.ctrl.go

@@ -80,27 +80,19 @@ func (controller *PayInvoiceController) PayInvoice(c echo.Context) error {
 		}
 	}
 
+	ok, err := controller.svc.BalanceCheck(c.Request().Context(), lnPayReq, userID)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		c.Logger().Errorf("User does not have enough balance user_id:%v amount:%v", userID, lnPayReq.PayReq.NumSatoshis)
+		return c.JSON(http.StatusBadRequest, responses.NotEnoughBalanceError)
+	}
+
 	invoice, err := controller.svc.AddOutgoingInvoice(c.Request().Context(), userID, paymentRequest, lnPayReq)
 	if err != nil {
 		return err
 	}
-
-	currentBalance, err := controller.svc.CurrentUserBalance(c.Request().Context(), userID)
-	if err != nil {
-		controller.svc.DB.NewDelete().Where("id = ?", invoice.ID).Exec(c.Request().Context())
-		return err
-	}
-
-	minimumBalance := invoice.Amount
-	if controller.svc.Config.FeeReserve {
-		minimumBalance += invoice.CalcFeeLimit(controller.svc.IdentityPubkey)
-	}
-	if currentBalance < minimumBalance {
-		c.Logger().Errorf("User does not have enough balance invoice_id:%v user_id:%v balance:%v amount:%v", invoice.ID, userID, currentBalance, invoice.Amount)
-		controller.svc.DB.NewDelete().Model(&invoice).Where("id = ?", invoice.ID).Exec(c.Request().Context())
-		return c.JSON(http.StatusBadRequest, responses.NotEnoughBalanceError)
-	}
-
 	sendPaymentResponse, err := controller.svc.PayInvoice(c.Request().Context(), invoice)
 	if err != nil {
 		c.Logger().Errorf("Payment failed invoice_id:%v user_id:%v error: %v", invoice.ID, userID, err)

controllers_v2/keysend.ctrl.go

@@ -182,7 +182,7 @@ func (controller *KeySendController) SingleKeySend(c echo.Context, reqBody *KeyS
 
 	minimumBalance := invoice.Amount
 	if controller.svc.Config.FeeReserve {
-		minimumBalance += invoice.CalcFeeLimit(controller.svc.IdentityPubkey)
+		minimumBalance += controller.svc.CalcFeeLimit(invoice.DestinationPubkeyHex, invoice.Amount)
 	}
 	if currentBalance < minimumBalance {
 		c.Logger().Errorf("User does not have enough balance invoice_id:%v user_id:%v balance:%v amount:%v", invoice.ID, userID, currentBalance, invoice.Amount)

controllers_v2/payinvoice.ctrl.go

@@ -95,7 +95,7 @@ func (controller *PayInvoiceController) PayInvoice(c echo.Context) error {
 
 	minimumBalance := invoice.Amount
 	if controller.svc.Config.FeeReserve {
-		minimumBalance += invoice.CalcFeeLimit(controller.svc.IdentityPubkey)
+		minimumBalance += controller.svc.CalcFeeLimit(invoice.DestinationPubkeyHex, invoice.Amount)
 	}
 	if currentBalance < minimumBalance {
 		c.Logger().Errorf("User does not have enough balance invoice_id:%v user_id:%v balance:%v amount:%v", invoice.ID, userID, currentBalance, invoice.Amount)

db/models/invoice.go

@@ -2,7 +2,6 @@ package models
 
 import (
 	"context"
-	"math"
 	"time"
 
 	"github.com/uptrace/bun"
@@ -42,15 +41,4 @@ func (i *Invoice) BeforeAppendModel(ctx context.Context, query bun.Query) error
 	return nil
 }
 
-func (i *Invoice) CalcFeeLimit(identityPubkey string) int64 {
-	if i.DestinationPubkeyHex == identityPubkey {
-		return 0
-	}
-	limit := int64(10)
-	if i.Amount > 1000 {
-		limit = int64(math.Ceil(float64(i.Amount)*float64(0.01)) + 1)
-	}
-	return limit
-}
-
 var _ bun.BeforeAppendModelHook = (*Invoice)(nil)

lib/service/invoices.go

@@ -117,7 +117,7 @@ func (svc *LndhubService) SendInternalPayment(ctx context.Context, invoice *mode
 func (svc *LndhubService) SendPaymentSync(ctx context.Context, invoice *models.Invoice) (SendPaymentResponse, error) {
 	sendPaymentResponse := SendPaymentResponse{}
 
-	sendPaymentRequest, err := createLnRpcSendRequest(invoice)
+	sendPaymentRequest, err := svc.createLnRpcSendRequest(invoice)
 	if err != nil {
 		return sendPaymentResponse, err
 	}
@@ -143,11 +143,11 @@ func (svc *LndhubService) SendPaymentSync(ctx context.Context, invoice *models.I
 	return sendPaymentResponse, nil
 }
 
-func createLnRpcSendRequest(invoice *models.Invoice) (*lnrpc.SendRequest, error) {
+func (svc *LndhubService) createLnRpcSendRequest(invoice *models.Invoice) (*lnrpc.SendRequest, error) {
 	feeLimit := lnrpc.FeeLimit{
 		Limit: &lnrpc.FeeLimit_Fixed{
 			//if we get here, the destination is never ourselves, so we can use a dummy
-			Fixed: invoice.CalcFeeLimit("dummy"),
+			Fixed: svc.CalcFeeLimit("dummy", invoice.Amount),
 		},
 	}
 

lib/service/invoices_test.go

@@ -7,12 +7,14 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var svc = &LndhubService{}
+
 func TestCalcFeeWithInvoiceLessThan1000(t *testing.T) {
 	invoice := &models.Invoice{
 		Amount: 500,
 	}
 
-	feeLimit := invoice.CalcFeeLimit("dummy")
+	feeLimit := svc.CalcFeeLimit("dummy", invoice.Amount)
 	expectedFee := int64(10)
 	assert.Equal(t, expectedFee, feeLimit)
 }
@@ -22,7 +24,7 @@ func TestCalcFeeWithInvoiceEqualTo1000(t *testing.T) {
 		Amount: 500,
 	}
 
-	feeLimit := invoice.CalcFeeLimit("dummy")
+	feeLimit := svc.CalcFeeLimit("dummy", invoice.Amount)
 	expectedFee := int64(10)
 	assert.Equal(t, expectedFee, feeLimit)
 }
@@ -32,7 +34,7 @@ func TestCalcFeeWithInvoiceMoreThan1000(t *testing.T) {
 		Amount: 1500,
 	}
 
-	feeLimit := invoice.CalcFeeLimit("dummy")
+	feeLimit := svc.CalcFeeLimit("dummy", invoice.Amount)
 	// 1500 * 0.01 + 1
 	expectedFee := int64(16)
 	assert.Equal(t, expectedFee, feeLimit)

lib/service/user.go

@@ -4,10 +4,12 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"math"
 
 	"github.com/getAlby/lndhub.go/common"
 	"github.com/getAlby/lndhub.go/db/models"
 	"github.com/getAlby/lndhub.go/lib/security"
+	"github.com/getAlby/lndhub.go/lnd"
 	"github.com/uptrace/bun"
 	passwordvalidator "github.com/wagslane/go-password-validator"
 )
@@ -91,6 +93,30 @@ func (svc *LndhubService) FindUserByLogin(ctx context.Context, login string) (*m
 	return &user, nil
 }
 
+func (svc *LndhubService) BalanceCheck(ctx context.Context, lnpayReq *lnd.LNPayReq, userId int64) (ok bool, err error) {
+	currentBalance, err := svc.CurrentUserBalance(ctx, userId)
+	if err != nil {
+		return false, err
+	}
+
+	minimumBalance := lnpayReq.PayReq.NumSatoshis
+	if svc.Config.FeeReserve {
+		minimumBalance += svc.CalcFeeLimit(lnpayReq.PayReq.Destination, lnpayReq.PayReq.NumSatoshis)
+	}
+	return currentBalance > minimumBalance, nil
+}
+
+func (svc *LndhubService) CalcFeeLimit(destination string, amount int64) int64 {
+	if destination == svc.IdentityPubkey {
+		return 0
+	}
+	limit := int64(10)
+	if amount > 1000 {
+		limit = int64(math.Ceil(float64(amount)*float64(0.01)) + 1)
+	}
+	return limit
+}
+
 func (svc *LndhubService) CurrentUserBalance(ctx context.Context, userId int64) (int64, error) {
 	var balance int64